With the continuous development of networking and internet protocol (IP) techniques, intelligent surveillance techniques based on IP and networking have developed rapidly. In addition, IP surveillance has become a main surveillance technique. Due to security and cost, most surveillance networks are disposed in private networks. In these types of surveillance networks, a mobile user or a public network user, acting as a Video Client (VC), will dial into a private enterprise network through L2TP when they access surveillance resources in the private enterprise network, as shown in FIG. 1.
After the user dials into the private enterprise network, a default route with a high priority is added to a host of the user. The next-hop of the route is an L2TP interface of the host of the user. A result of this is that when the user visits other servers on the public network, packets will first be transmitted to the L2TP server, i.e., the export of the private enterprise network, before being forwarded to a public network server, as shown in FIG. 2. If there is an access restriction on the export of the private enterprise network or access to the public network is prohibited on the export of the private enterprise network, the public network user will be affected and bandwidth resources of the export of the private enterprise network are wasted.